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Serving South San Francisco, CA and surrounding areas. (650) 822-6266
The best asphalt is only as good as what is underneath it. We excavate unstable soil, establish the correct slope, compact a solid base, and hand off a subgrade that holds through Bay Area wet seasons and hillside terrain.
Grading and excavation in South San Francisco means removing unstable soil and reshaping the ground to the correct level and slope before any paving begins - for a typical residential driveway, excavation and base preparation takes one to two days, and the work is what determines whether the asphalt you put on top lasts five years or twenty.
This is the step that most failed driveways skipped. When the ground underneath asphalt was not properly excavated, compacted, and sloped, the surface cracks, sinks, and heaves as the soil shifts beneath it. On the San Francisco Peninsula, clay soils are the main culprit - they swell with winter rain and shrink in summer, and that seasonal movement stresses pavement from below regardless of how good the asphalt is. Excavating and replacing that clay with a stable compacted aggregate base is the fix.
Grading is also a drainage project. How your driveway is sloped determines where water goes when it rains - and a correctly graded surface channels water away from your home. Proper base work goes hand-in-hand with the right drainage solutions to keep water moving the right direction across your entire property.
After rain, standing water collects in one or more areas of your driveway and takes a long time to drain away. In South San Francisco's wet season, this is a clear sign the surface was not graded correctly - or has settled unevenly over time. Left alone, those wet spots soften the base and lead to cracking or sinking within a season or two.
A network of cracks spreading across the surface, especially patterns that look like alligator skin, usually means the base has shifted underneath. On the Peninsula, clay soil movement is often the underlying cause. Patching the surface without addressing what is below is a short-term fix at best.
Parts of your driveway are noticeably higher or lower than they used to be, creating an uneven surface that is hard on tires and potentially a trip hazard. This kind of movement usually means the base material shifted or was never properly compacted in the first place.
Instead of flowing away from your house, water from rain or irrigation is running toward your foundation or garage door. This is a grading problem, and it is worth fixing promptly - water near a foundation causes far more expensive damage than a driveway replacement.
We handle grading and excavation for new driveway installations, full replacements, and drainage correction projects across South San Francisco. Our crew uses excavators, skid steers, and plate compactors to remove existing surface material and unstable soil, bring the ground to the correct elevation and slope, install and compact a crushed aggregate base layer, and deliver a subgrade ready for asphalt. Every job starts with a site visit to look at your specific ground conditions - South San Francisco's terrain varies significantly from the flat streets near the bay to the hillside lots in Westborough and Buri Buri, and the grading approach for a sloped lot is different from a flat-grade installation. Drainage planning is built into every project: we determine the correct slope direction before a shovelful of soil is moved. This connects directly with our concrete curbing and sidewalks work - proper grading and curbing work together to control where water goes on your property.
Permit requirements depend on the scope of the project. Minor regrading on private property often does not require a permit, but significant soil disturbance, drainage changes, or work near the public right-of-way typically does. We know South San Francisco's thresholds and pull whatever permits are required before equipment arrives - you do not have to navigate city paperwork on your own. For projects that also require proper water management after grading is complete, we coordinate with our drainage solutions team so the finished surface handles Bay Area rainfall correctly.
Best for homeowners starting fresh - removes existing surface and unstable soil, installs a compacted aggregate base at the right slope, and delivers a subgrade ready for new asphalt.
Suited for driveways that pitch toward the home or collect standing water - reshapes the surface slope so water flows away from your foundation and garage, not toward it.
For South San Francisco's hillside properties in Westborough, Buri Buri, and above Grand Avenue - requires specific excavation and base engineering that flat-lot grading does not account for.
For driveways where the existing base has failed entirely - demolishes the old surface, excavates clay and unstable material, and builds a new compacted base from the ground up.
South San Francisco sits on the San Francisco Peninsula where two things make grading work significantly different from what you might encounter elsewhere. First, much of the city is built on expansive clay soils that swell when saturated with winter rain and shrink during the dry summer months. That seasonal movement is the single biggest reason driveways here crack and shift, and it means proper excavation cannot simply level the ground - it means removing the clay to sufficient depth and replacing it with a compacted aggregate base that does not move. Skipping this step, or not going deep enough, produces the same failing driveway a few years later. Homeowners in South San Francisco neighborhoods from the flatlands near the bay to the hillside streets of Westborough deal with this consistently - it is a function of the soil, not the quality of the old asphalt.
Second, many South San Francisco properties sit on sloped lots, and water moves fast on hillside terrain. The Millbrae and peninsula communities share the same hillside topography and drainage challenges, and a grading contractor who understands how water behaves on these lots will design the slope of your base to shed water cleanly - not just level the ground and hope for the best. The Bay Area also has regional stormwater rules that govern how runoff leaves your property. A contractor familiar with local requirements accounts for these during the grading design so your project meets the standard without you having to research it yourself.
Call or submit a form and we schedule a free on-site visit within one business day. We look at your ground conditions, measure slope and drainage direction, and flag any permit requirements before giving you a written estimate.
If your project requires a grading or right-of-way permit, we pull those on your behalf. Before any digging begins, we arrange underground utility locating - a service that marks gas, water, and electrical lines to protect your property and the crew.
The crew removes the existing surface and unstable soil, shapes the ground to the correct elevation and slope, and installs crushed aggregate base material. In South San Francisco, this often means digging out clay-heavy soil that shifts with the seasons.
Base material is compacted in layers - we check for soft spots before moving on. If a permit inspection is required, that happens here. Once the base passes, the site is ready for asphalt and we walk you through the drainage slope and what to expect next.
Free on-site estimate. We look at your ground conditions and tell you exactly what will hold - and what will not.
(650) 822-6266South San Francisco and much of the Peninsula sit on expansive clay soils that swell and shrink with the seasons. We know how deep to excavate to reach stable material, what aggregate base performs best in these conditions, and how to compact it so the surface above does not follow the soil movement below. This is the work that makes a paved surface last here.
Grading is a drainage project as much as a paving project. Before we move any soil, we establish where water needs to go when it rains - away from your home, not toward it. A contractor who can explain the drainage plan clearly in plain language before work starts is one who has actually thought it through, as the National Asphalt Pavement Association consistently emphasizes in its base preparation standards.
We know South San Francisco's grading permit thresholds and pull whatever the project requires before any digging begins. You will not end up with a stop-work order or a permit pulled after the fact - the paperwork is handled on the front end so the project moves without interruption.
If your driveway's surface issues are coming from a failed base, we will tell you that rather than recommend a resurface that will fail again. If minor regrading is all your project needs, we will say that too. You get a written scope of work that reflects what we actually found, not what produces the bigger job.
Keystone South SF Asphalt Paving works across South San Francisco and the surrounding peninsula - from the flat neighborhoods near the bay to the hillside lots above Grand Avenue. We carry state contractor licensing verifiable through the California Contractors State License Board, full liability insurance, and workers' compensation coverage.
Add curbing and concrete edges that work with your graded surface to control water movement and protect the perimeter of your paved area.
Learn MoreInstall catch basins, channel drains, and other drainage infrastructure that manages water across your property once the ground is properly graded.
Learn MoreSouth San Francisco's wet season starts in November. Schedule your grading project now and have a solid base in place before the rain returns.